[docs] Update docs

[satterly]

general

• [x] server settings 6fd0aa68a89b041f27dd3613a8071d8e8d8cbd16
• [ ] web ui - currently only headings
• [x] integrations - webhooks are incomplete
• [ ] customer views - almost nothing

tutorials

• [x] tutorial 1 deploy
• [x] tutorial 2 housekeeping
• [x] tutorial 3 plugins
• [ ] tutorial 4 alerts - (wip) groups, types, origins, tags, custom attributes, raw data
• [x] tutorial 5 blackouts . (wip) resource, service, event, group, res-evt, tag, accept
• [ ] tutorial 6 authentication & authorization
• [ ] tutorial 7 customer views
• [ ] tutorial 8 integration nagios
• [ ] tutorial 8 integration zabbix
• [ ] tutorial 9 webhooks
• [ ] tutorial 9 trouble shooting
• [x] tutorial 10 docker
• [ ] fix links at the bottom of each tutorial
• [ ] add links to tutorials in each relevant page

reference

• [x] API
• [x] alert format
• [x] heartbeat format

[satterly]

Docs